Has anybody else used that Cooler Mash tun set-up? I just put it together and used it and the beer is quite off. When I first tested it with water to see how well it would insulate I noticed a film of something on top of the water. Does anyone know if there is something that needs to be done to the cooler to get off a layer of whatever before mashing will work? It's a Rubbermaid 48 quart cooler. Thanks.

I use an old ice chest which had been used for several years beforehand, and had therefore been cleaned out an innumerable number of times. But it does seem to me, IIRC, that brand new ice chests usually have a sort of plastic odor when they're first opened, don't they? Odor means particles that are getting into your nose and which will likewise get into your beer. Anyway, I'm sorry to hear that you've apparently messed up a batch, but I wouldn't toss it just yet. I've had a couple of real stinky fermentations that still made a decent beer. Before doing another batch, I'd wash that ice chest out real good with a good soap and degreaser, then maybe let it soak a day or two with a bleach solution and/or some baking soda, and then air it out for as long as it takes to get rid of virtually all of the 'new ice-chest' odor before using it again.

I used B-bright (Oxyclean is the same chemical) to clean my cooler before the first use and had no flavor contribution to my beer. I use a Rubbermaid cooler and it really had no smell after that first cleaning. Oxiclean is a lot like baking soda and peroxide combined. As a matter of fact, after a day or so the peroxide has mostly broken down and you have little more than a baking soda solution.

Since you describe an oily film, you may want to use something with a bit more detergent action. Powderred Brewery Wash (PBW) is a good choice at a tablespoon or two per gallon. You can make your own with Oxyclean and TSP-Substitute (a great detergent you can get at the hardware store, usually in the paint section). PBW is 2 parts of one and one part of the other, but I always forget which, so I just add a tablespoon of each to a gallon and it works well.

Bleach is very effective at removing some smells, but be aware that it can add a bad flavor to your beer if not thoroughly rinsed out before use. It can also break down the plastic over time, so keep the bleach exposures short and dilute it to about 5%. At that concentration it will also disinfect in 10 minutes. I reserve bleach for the most intractable problems in brewing.